In the use of shotguns, it is often desirable to install choke tubes at the end of the barrel to modify the shot pattern of the gun. The choke tubes typically screw into threads formed in the ends of the barrels, using a tool supplied with the tube. It has been found inconvenient for hunters to carry separate tools to install and remove the choke tubes for varying sizes of shotguns, but a suitable alternative has heretofore not been available.